FAR 21.9 — Replacement Parts
FAR 21.9 explains who can produce replacement and modification parts for type-certificated aircraft, including PMA, standard parts, and owner-produced parts.
FAR 21.9 controls who is allowed to produce parts that are likely to be installed on a type-certificated aircraft. The goal is to keep unapproved or counterfeit parts off certified aircraft, because every installed part affects airworthiness.
If a person knows (or should know) a part will be installed on a type-certificated product, they may only produce it if it falls into one of these categories:
- Produced under a type certificate
- Produced under an FAA production approval (such as a PMA, TSO, or production certificate)
- A standard part (e.g., a nut or bolt) made to a government or industry specification (like AN, MS, or NAS)
- A commercial part as defined in § 21.1
- Produced by the owner or operator for maintaining or altering their own aircraft (owner-produced parts)
- Fabricated by a certificate holder with a quality system and consumed during a repair or alteration under Part 43
- Produced in any other manner specifically approved by the FAA
A producer also may not market a part as suitable for installation on a type-certificated product unless it was made under a TC or FAA production approval. For aircraft certificated under §§ 21.25(a)(2) or 21.27 (surplus military), parts must have been declared surplus by the U.S. Armed Forces and intended for that model.
Why it matters: As a pilot or owner, this rule is your basis for verifying that every replacement part installed on your airplane is legally airworthy.